unswizzled chara texture data in the game Yahari Game demo Ore no Seishun Love Come wa Machigatteiru.

chara.py

#unswizzled texture data in the game Yahari Game demo Ore no Seishun Love Come wa Machigatteiru.
#for some reason the game didn't use the float encode for src_x and src_y like in https://github.com/AbsurdlySuspicious/sg-sprite/blob/master/lay-format.md
import cv2
import struct
import numpy as np

#i think the x and y use some mapping algorithm, but for now i will use a look up table
x_table = { #width = 2048 --> 64 x_chunks
    0x3A000000:  0,

    0x3C840000:  1,

    0x3D020000:  2,
    0x3D420000:  3,

    0x3D810000:  4,
    0x3DA10000:  5,
    0x3DC10000:  6,
    0x3DE10000:  7,
    0x3E008000:  8,

    0x3E108000:  9,
    0x3E208000: 10,
    0x3E308000: 11,
    0x3E408000: 12,
    0x3E508000: 13,
    0x3E608000: 14,
    0x3E708000: 15,
    
    0x3E804000: 16,
    0x3E884000: 17,
    0x3E904000: 18,
    0x3E984000: 19,
    0x3EA04000: 20,
    0x3EA84000: 21,
    0x3EB04000: 22,
    0x3EB84000: 23,
    0x3EC04000: 24,
    0x3EC84000: 25,
    0x3ED04000: 26,
    0x3ED84000: 27,
    0x3EE04000: 28,
    0x3EE84000: 29,
    0x3EF04000: 30,
    0x3EF84000: 31,
    
    0x3F002000: 32,
    0x3F042000: 33,
    0x3F082000: 34,
    0x3F0C2000: 35,
    0x3F102000: 36,
    0x3F142000: 37,
    0x3F182000: 38,
    0x3F1C2000: 39,
    0x3F202000: 40,
    0x3F242000: 41,
    0x3F282000: 42,
    0x3F2C2000: 43,
    0x3F302000: 44,
    0x3F342000: 45,
    0x3F382000: 46,
    0x3F3C2000: 47,
    0x3F402000: 48,
    0x3F442000: 49,
    0x3F482000: 50,
    0x3F4C2000: 51,
    0x3F502000: 52,
    0x3F542000: 53,
    0x3F582000: 54,
    0x3F5C2000: 55,
    0x3F602000: 56,
    0x3F642000: 57,
    0x3F682000: 58,
    0x3F6C2000: 59,
    0x3F702000: 60,
    0x3F742000: 61,
    0x3F782000: 62,
    0x3F7C2000: 63,
}

y_table = { #height = 1024 --> 32 y_chunks
    0x3A800000:  0,

    0x3D040000:  1,

    0x3D820000:  2,
    0x3DC20000:  3,

    0x3E010000:  4,
    0x3E210000:  5,
    0x3E410000:  6,
    0x3E610000:  7,

    0x3E808000:  8,
    0x3E908000:  9,
    0x3EA08000: 10,
    #below is what i guess, not taken from any file, may be incorrect so need further test
    0x3EB08000: 11,
    0x3EC08000: 12,
    0x3ED08000: 13,
    0x3EE08000: 14,
    0x3EF08000: 15,

    0x3F004000: 16,
    0x3F084000: 17,
    0x3F104000: 18,
    0x3F184000: 19,
    0x3F204000: 20,
    0x3F284000: 21,
    0x3F304000: 22,
    0x3F384000: 23,
    0x3F404000: 24,
    0x3F484000: 25,
    0x3F504000: 26,
    0x3F584000: 27,
    0x3F604000: 28,
    0x3F684000: 29,
    0x3F704000: 30,
    0x3F784000: 31,
}

tex_png = '.\\output\\0124' #gxt file, converted to png so cv2 can read
lay = '.\\output\\0125' #the file that goes right next to the gxt file

src_im = cv2.imread(tex_png, cv2.IMREAD_UNCHANGED)

f = open(lay, 'rb')
lay_dat = bytearray(f.read())
f.close()

#init
sprite_count = struct.unpack('<I', lay_dat[0: 4])[0]
chunk_count = struct.unpack('<I', lay_dat[4: 8])[0]

sprite_start = 0x8
sprite_length = 0xC * sprite_count
chunk_start = sprite_start + sprite_length
chunk_length = chunk_count * 0x10
print(sprite_count, chunk_count)

min_x = 0
max_x = 0
min_y = 0
max_y = 0

for i in range(chunk_count):
    dst_x, dst_y = struct.unpack('<2f', lay_dat[chunk_start + i * 0x10 : chunk_start + i * 0x10 + 8])
    dst_x, dst_y = int(dst_x), int(dst_y)
    min_x = min(min_x, dst_x)
    max_x = max(max_x, dst_x + 32)
    min_y = min(min_y, dst_y)
    max_y = max(max_y, dst_y + 32)

x_offset = -min_x
y_offset = -min_y
w, h = max_x - min_x, max_y - min_y
del min_x, max_x, min_y, max_y
print(w, h)

sprites_raw = []

#refer to https://github.com/AbsurdlySuspicious/sg-sprite/blob/master/lay-format.md
for i in range(sprite_count): #generate sprite
    sprites_raw.append(np.zeros((h, w, 4), np.uint8))
    #read sprite info
    s_a, s_b, s_c, s_d = struct.unpack('<4B', lay_dat[sprite_start + i * 0xC : sprite_start + i * 0xC + 4])
    #skip for now
    s_chunk_offset, s_chunk_count = struct.unpack('<2I', lay_dat[sprite_start + i * 0xC + 4 : sprite_start + i * 0xC + 12])
    s_chunk_offset *= 0x10
    for c in range(s_chunk_count):
        c_dst_x, c_dst_y = struct.unpack('<2f', lay_dat[chunk_start + s_chunk_offset + c * 0x10 : chunk_start + s_chunk_offset + c * 0x10 + 8])
        c_dst_x, c_dst_y = int(c_dst_x) + x_offset, int(c_dst_y) + y_offset
        chunk_x, chunk_y = struct.unpack('<2I', lay_dat[chunk_start + s_chunk_offset + c * 0x10 + 8: chunk_start + s_chunk_offset + c * 0x10 + 16])
        #print(hex(chunk_x), hex(chunk_y))
        chunk_x, chunk_y = x_table[chunk_x], y_table[chunk_y]
        #print(chunk_x, chunk_y)
        sprites_raw[i][c_dst_y : c_dst_y + 32, c_dst_x : c_dst_x + 32, :] = \
            src_im[chunk_y * 32 : chunk_y * 32 + 32, chunk_x * 32 : chunk_x * 32 + 32, :]
    #could generate layered images (TIFF?), but i will just let it show the layers here
    cv2.imshow('', sprites_raw[i])
    cv2.waitKey(0)

cv2.destroyAllWindows()